The invention relates to defect detection methods, and more particularly, to discover defect locations by spraying locating particles on a wafer.
In semiconductor manufacturing, wafers are inspected to discover defects using inspection tools during etching, developing, deposition, and other processes. As critical dimensions for semiconductor processes are gradually decreased and precision and accuracy for wafer inspection are progressively increased. To confirm product quality, high resolution optical instruments for integrated circuit (IC) manufacture/design must be employed to implement inspection processes. These processes comprise inspection after etching (AEI), inspection after developing (ADI), quality assurance (QA), quality control (QC), and others.
Wafer inspection mainly locates defects on a chip. Conventional wafer probe tests comprise testing related electrical characteristics of all memory cells (arrayed in a matrix) on a chip, displaying coordinates of failed memory cells in the form of fail bit mapping (FBM), according to test results, in a coordinate region defined by X and Y axes, and estimating failure reasons according to analyzed FBM types, such as point-fail, block-fail, or line-fail. Fail bit mapping is an abnormal analysis method for semiconductor components, visualizing addresses of abnormal memory cells for confirmations.
Additionally, conventional wafer inspection methods further inspect wafers using an optical microscope, a scanning electron microscope (SEM), or a transmission electron microscope (TEM). The described microscopes are widely employed in wafer and mask inspection and further employed in crystal liquid display (LCD), compact discs, hard discs, QC and process management applications, nanotechnology, micro-electro-mechanical systems, and others.
Current inspection methods, however, have reached a bottleneck, and are incapable of further re-detection when extremely small (less than 100 nm) particles or defects on wafers are detected, particularly for unpatterned wafers. When extremely small (10 nm or less) particles or defects are detected, unpatterned wafers are employed to improve yields. Tiny defects, however, affect critically, such that defect re-detection is important. Additionally, different tool settings (alignment coordinates, for example) may reduce the success rate for re-detection.
Thus, an improved wafer defect detection method for extremely small particles or defects is desirable.